This invention relates to an improved method and apparatus for manipulating large sections of artificial turf and the artificial turf installation per se during manipulation, and more specifically to an improved method and apparatus facilitating repeated covering and uncovering of a rigid surface with such turf.
Artificial turf installations have become quite widespread for indoor and outdoor uses. In a typical convertible indoor artificial turf installation, rectangular-shaped sections of artificial turf have been installed to removably cover a support surface. The turf sections may be repeatedly rolled up and stored after each use so that the area underneath can be used for other purposes. For example, such a convertible system has been used to manually cover a basketball floor with synthetic turf where it is used for football practice and then manually rolled up and stored nearby in large rolls to expose the floor for use in playing basketball. Aside from the need for extensive manpower to roll out and roll up the large sections of artificial turf, the drawback to this approach is the lack of an effective way to manipulate the large artificial turf area to remove wrinkles which developed during the roll-up and roll-out phases.
Significant improvements are disclosed in U.S. Pat. Nos. 4,399,954 and 4,738,407, incorporated herein by reference, which disclose the manipulation of large sections of artificial turf supported on a pneumatic cushion. To cover a field, the artificial turf is pulled from a roll of artificial turf supported along its length by support rollers. For instance, artificial turf sufficient to cover an entire football field can be pulled from the roll because friction between the artificial turf and the support surface is minimized with a pneumatic cushion, provided by a blower feeding low pressure air to a few ports installed in the surface in a row adjacent the roll, which is often stored below grade in a large covered pit. When the field is extended, the blower is shut down, allowing the artificial turf to settle onto the support surface. The artificial turf can be rapidly removed by applying a pneumatic cushion then winding the artificial turf onto the roll, for instance by driving the support rollers.
Such a rapid field conversion system has benefited the management of multi-use stadia by allowing the scheduling of events more closely together to maximize facility use. For instance, a football game can be played on artificial turf supported over a basketball court the same day as a basketball game due to the minimal time required for field conversion, often less than one hour.
Another significant improvement is disclosed in U.S. Pat. No. 4,588,189, incorporated herein by reference, which discloses the manipulation of large, irregularly shaped sections of artificial turf supported on a pneumatic cushion by utilizing an apparatus comprising at least one belt removably attached to an oblique margin of the artificial turf to provide non-deflecting support for a roll of artificial turf wrapped onto an elongated cylindrical pole.
A principal disadvantage of such rapid field conversion systems is that their components occupy valuable space within the facility which could be more efficiently utilized.
Another disadvantage of such systems was the lack of a means for protecting the rope-like members used to roll and unroll the turf sections from the damaging effects of friction with the floor and other support surfaces.
Similarly, heretofore, the pneumatic means for developing low air pressure underneath the artificial turf required installation below ground level of an air blower or air transmission ducts.
Another disadvantage of such rapid field conversion systems is that the cylindrical core on which the turf is rolled and stored may shift horizontally during winding and unwinding, resulting in harmful stresses upon the artificial turf and elongation of the roll of turf as it is rolled and unrolled. Such elongation of the roll may interfere with the proper operation of the system or result in misalignment of the turf when covering the desired surface.
Finally, current rapid field conversion systems have no means for adjusting the rate of rolling and unrolling the artificial turf. This can result in undesirable stresses upon the turf and other components of the apparatus when sudden jolts are encountered during the commencement and termination of rolling.
Thus, a need exists in the prior art for an improved system to conveniently manipulate large sections of artificial turf in a convertible installation involving multiple coverings and uncoverings of a rigid support surface.